When you have unused cards at the end of a race or leg (Virtual Regatta buys them back for you!)

Credits earned as a finish bonus and credits from the purchase of your unused cards are added to your permanent credits: they can be used at any time, regardless of the race in which you will later participate.

Credits obtained as a starting bonus may only be used on the race on which they were obtained. If they were not entirely spent at the end of the race or leg you received them on, they will disappear.